dev-ml/lablgtk-1.2.5 needs dev-libs/libxml (/usr/lib/libxml.so). Made patch to include it in DEPEND. Maybe this is an issue for the other versions as well. Please add it when needed.
Created attachment 47968 [details, diff] Adding dev-libs/libxml to DEPEND
Created attachment 47969 [details, diff] Correct patch, previous was reversed. Sorry.
Works for me now.